JP4761625B2 - Uranium oxide transport container - Google Patents

Description

[0001]
TECHNICAL BACKGROUND OF THE INVENTION
The present invention relates to a container for transporting uranium oxide in a plurality of independent canisters in an outer container, and more specifically, uranium oxide per unit volume that is particularly configured to ensure critical safety. The present invention relates to a uranium oxide transport container arranged to maximize its mass.
[0002]
Currently, uranium oxide is transported in multiple independent canisters similar to conventional 55 gallon drums. Each container includes an outer metal sleeve surrounding the thermal insulation layer. The heat insulating layer surrounds and encloses a single inner canister containing uranium oxide. Such drum-like containers are typically transported in a seaburn carrier, which is basically a large trailer-sized transport carrier having a general dimension of 20 × 8 × 8. Current practice is to individually load approximately 54 drum-like containers as described above into a sea burn that meets the need to ensure critical safety (ie, the need to control neutron movement to avoid critical mass). However, the capacity of uranium oxide that can be transported in such drum canisters is relatively small, and each container must be handled individually. Therefore, it is recognized that it is necessary to transport uranium oxide more efficiently to increase the mass of uranium oxide per unit volume, thereby reducing labor and transportation costs while ensuring critical safety.
[Patent Document 1]
US Pat. No. 3,935,467 issued in January 1976 [Patent Document 2]
US Patent No. 40233317 issued in May 1977 [Patent Document 3]
US Patent No. 4560069 issued in December 1985 [Patent Document 4]
US Pat. No. 4,803,042 issued in February 1989 [Patent Document 5]
US Pat. No. 4,815,605 issued in March 1989 [Patent Document 6]
US Patent No. 5438597 issued in August 1995 [Patent Document 7]
Japanese Patent Application Laid-Open No. 61-259985 and US Patent No. 4560069 [Patent Document 8]
JP-A-01-162195 Japanese Patent Application No. 4,803,042 [Patent Document 9]
Japanese Patent Application No. 4815605, Japanese Patent Laid-Open No. 63-222299 [Patent Document 10]
Japanese Patent Application No. 08-507382, US Pat. No. 5,438,597
SUMMARY OF THE INVENTION
In an embodiment of the present invention, there is provided a new and improved multi-cavity uranium oxide transport container that accommodates a plurality of inner containers so as to guarantee critical safety and greatly increase the mass of uranium oxide per unit volume that can be transported. The Specifically, the present invention provides an outer container having a container body and a lid. The container body includes a regular array of cavities for receiving individual inner containers containing uranium oxide. In order to ensure critical safety while maximizing the mass per unit volume, each inner container has a side wall on which a nuclear poison and a nuclear moderator are stacked. For example, the stainless steel inner wall of the inner container is lined with cadmium, which is a nuclear poison, and polyethylene, which is a moderator. The moderator decelerates neutrons and captures them by cadmium poisons. A ceramic material may be laminated on the moderator and poison to increase fire resistance. The uranium oxide may be placed in a separate pail or bag and then placed in the inner container, which has a lid for sealing it.
[0004]
The cavity of the outer container preferably comprises a cylindrical sleeve made of stainless steel that stands upright from the bottom of the outer container in a regular array (eg, a preferred 3x3 array). The space between the sleeves is filled with a foamed plastic material such as polyurethane foam. The space between the outermost inner container and the outer container wall is similarly filled with a foam material such as polyurethane foam. However, the latter outer space contains a foam material having a higher density than that of the inner foam material. As a result, the high density foam material on the outer periphery of the container body forms a fire and impact resistant layer between the container body and the inner container, and the low density foamed plastic material forms an additional fire and impact resistant material. A cover plate is provided above the container body, and individual openings are provided at positions corresponding to the sleeves in the container body so that the inner container can be easily disposed in the sleeve.
[0005]
The outer container includes a lid that seals the container body in use. The lid includes a layer of high density foamed plastic material such as polyurethane on its lower surface. The plastic material is provided with a plurality of downwardly opened recesses for receiving the upper end portion of the inner container protruding through the opening of the cover plate. As a result, the inner container is completely enclosed in the outer container, and an impact resistant and fire resistant foam is provided between the inner containers and between the inner container and the outer container.
[0006]
In a preferred embodiment of the present invention, the outer container body includes a plurality of pairs of elongated, substantially rectangular pockets for inserting the forks of the forklift, and the pockets are formed so as to cross each other. In this manner, the outer container can be lifted by inserting the fork of the forklift into the pocket from any side of the container. Further, one or more plugs made of a material that can be melted at a predetermined temperature are provided on the wall of the outer container. In the event of a fire, the foamed gas of the foamed plastic material is released through the opening opened by melting the plug, preventing the container from bursting.
[0007]
In a preferred embodiment of the present invention, there is provided a uranium oxide transport container comprising an outer container and a plurality of storage inner containers arranged in a regular array spaced apart from each other in the outer container. Each storage container is made of a cylinder for containing a predetermined amount of uranium oxide, and the cylinder has a sealed top, a sealed bottom, and a cylindrical side wall in which a nuclear poison and a nuclear moderator are stacked, A transport container is provided in which the space between the storage containers and between the storage container and the outer container is filled with a plastic material.
[0008]
[Preferred Embodiment]
Referring to the drawings, and in particular to FIG. 1, a conventional container for transporting uranium oxide (shown generally at 10) is shown. The container 10 includes an inner canister 12 containing uranium oxide, and an outer container 14 that surrounds the inner canister 12 and has a detachable lid 16. The heat insulating material is disposed between the outer wall and the lid and the inner canister 12. (Generally plastic material). Container 10 is similar to a standard 55 gallon drum and has been used as a standard shipping container for uranium oxide for many years.
[0009]
Referring now to FIG. 2, a container constructed in accordance with the present invention (shown generally at 20) is shown, which includes an outer container body 22 and a lid 24. The outer container body 22 is substantially rectangular, and has a side wall 26, a bottom wall 28, and a top wall 30 for confining a plurality of inner containers, generally indicated by reference numeral 32 in FIG. A plurality of cavities, preferably defined by a contamination sleeve 34, are provided in the outer container body 22, in which the inner container is stored for transport. Before describing the outer container body and its lid in detail, the inner container will be described first.
[0010]
Referring to FIGS. 3 and 4, each inner container includes a bottom wall 36, an upper lid L, and a cylindrical side wall 38. The inner wall 40 and the outer wall 42 constituting the bottom wall 36 and the side wall 38 are made of stainless steel. Between the inner wall 40 and the outer wall 42 of the side wall 38, a layered structure including a nuclear poison 44 and a nuclear moderator 46 is preferably disposed. As shown most clearly in FIG. 4, the nuclear poison 44 covers the outer surface of the inner wall 40 and the nuclear moderator 46 covers the outer surface of the nuclear poison 44. The nuclear poison 44 is preferably made of cadmium for neutron absorption, and the nuclear moderator 46 is preferably made of a plastic material (such as polyethylene). Optionally, a ceramic layer 48 may be inserted between the nuclear moderator 46 and the outer wall 42 of the side wall 38 to add a fire protection structure. In this way, the nuclear poison, the nuclear moderator and the appropriate ceramic layer are inserted between the inner wall 40 and the outer wall 42 of the side wall 38. The bottom wall 36 and lid L are preferably free of nuclear toxins, moderators and ceramic materials, but may contain these materials as desired. Uranium oxide may be placed in a pail can P and placed in the inner container 32, and three such members P are shown in FIG.
[0011]
5 to 8 show three connection mechanisms between the lid L and the side wall 38 of the inner container 32. Referring to FIG. 5, the mounting roll flange 50 is formed by winding the side wall 38 outward. The lid La includes a peripheral annular groove 52 for covering the roll flange 50. An appropriate seal may be provided between the lid La and the flange. This form of lid can be reinforced with a plate 54 welded to the bottom of the lid. A suitable clamp (not shown), such as an annular C-shaped clamp, may be placed around the groove 52 and flange 50 to secure the lid La to the container 32. An appropriate seal (not shown) such as an O-ring seal may be inserted between the flange 50 and the groove 52 to seal the container 32.
[0012]
Referring to FIG. 6, a mounting flange 60 is fixed to the side wall 38 of the inner container 32, preferably by welding. The mounting flange 60 has an annular flange 62 facing outward. The lid Lb in this form has a flange 64 facing outward in the radial direction for covering the flange 62. An O-ring type seal 66 is provided between the flanges 62 and 64. The lid Lb includes a plurality of handle elements 68 protruding from the outer surface of the lid so that the inner container 32 can be handled by a machine such as a crane.
[0013]
In order to fix the lid Lb of FIG. 6 to the mounting flange 60, a substantially C-shaped annular clamp 70 is wound around the butting flanges 62 and 64, and both ends are welded to each other. The outer tightening band 72 is fixed around the clamp 70. The band 72 has screw parts at both ends thereof, and the band 72 around the clamp 70 is tightened by the screw tightening action.
[0014]
Referring to FIGS. 7 and 8, the lid Lc is a substantially flat lid having a plurality of bolt holes around it. A flange 74 having a threaded stop hole 76 is attached to the inner container side wall. An annular seal 78 (preferably made of silicone rubber) is provided between the lid Lc and the mounting flange 74, and has an opening 80 at a position matching the bolt hole of the lid and the blind hole of the mounting flange. After the lid Lc is placed on the mounting flange 74 and the bolt hole and the seal hole are aligned, the bolt 82 may be screwed into the mounting flange to fix the lid to the inner container.
[0015]
2 and 9, the outer container body 22 described above includes a plurality of upstanding sleeves 34 that form a contamination barrier. The sleeve 34 has an upper open end for containing the inner container. Therefore, the contamination in the sleeve 34 can be easily removed because the surface of the contamination barrier is smooth. As illustrated, the cavities in the outer container body for accommodating the inner container are arranged in a regular array (preferably a 3 × 3 array). Surrounding the sleeve 34 and filling the remainder of the volume of the container body 22 is a plastic material, preferably a polyurethane foam material. The polyurethane foam is placed in the container body in two different densities. The first foam 90 is disposed between the sleeves 34, that is, in a gap between the sleeves 34, and has a predetermined density (for example, 6 to 10 lb / ft ³ ). A high density polyurethane foam 92 is disposed between the side wall 26 of the outer container body 22 and the inner surface of the low density polyurethane foam. The density of this second high density foam can be approximately 15 lb / ft ³ . This foam reinforces the container and provides shock absorption as well as fire resistance. The high-density foam 92 is also disposed on the bottom wall 28 of the outer container body 22 as shown in FIG. Thus, when the sleeve 34 is accommodated, the inner wall is partitioned from the side wall 26 by the high-density foam and the low-density foam, and is partitioned from the bottom wall by the high-density foam.
[0016]
Before describing the lid 24 of the outer container, referring again to FIG. 2, a pair of vertically extending rectangular guides 96 are provided at the bottom of the container and open on each side of the container. The guides 96 are spaced apart from each other and receive the forks of the forklift through their open ends. Since the guides are open in pairs on each of the four side surfaces of the container, the container can be lifted from any side by a forklift. Furthermore, a plastic plug 98 (FIGS. 2 and 11) penetrating the side wall 26 is provided at one or more locations around the outer container body 22. The plug is made of a material that melts at a predetermined temperature. When the plug is melted, an opening that penetrates the side wall 26 is opened, and the inside of the container communicates with the surrounding environment. As a result, even if the container is exposed to a high temperature such as a fire, the gas generated from the heated plastic material in the container can be extracted, and the outer container main body 22 can be prevented from bursting. Further, a plurality of protruding screw sockets 100 are provided at intervals inside the side wall for screwing bolts to fix the lid 24 to the outer container body 22. Further, the length of the inner container 32 exceeds the length of the sleeve 34, and the upper end portion of the inner container protrudes through an opening provided in the top wall 30 of the outer container body 22.
[0017]
Referring now to FIGS. 12 and 13, the lid 24 includes a top wall 102, four side walls 104 depending from the top wall 102, and four reinforcing gussets 106 formed at the corners of the lid 24. . The lid 24 also includes a plurality of bolt holes for inserting bolts 108 for bolting the lid 24 to the body 22.
[0018]
A foamed plastic material 110 such as a high density polyurethane foam formed on the outer edge of the container body is provided on the lower surface of the top wall 102 of the lid 24. A plurality of recessed portions 112 (FIG. 13) are formed below the foamed plastic material 110 at positions corresponding to openings that penetrate the top wall 30 of the container body in order to accommodate the upper end portion of the inner container. As shown in FIG. 13, the recessed portion 112 has a shape complementary to the shape of the upper end portion of the inner container. The recessed portion is provided with a bolt for clamping the lid of the inner container so that the inner container 32 is firmly fixed in the container 20 when the inner container is accommodated in the sleeve 34 and the lid is attached to the container body 22. It is also formed to accommodate.
[0019]
Although the present invention has been described above with respect to embodiments that are considered to be the most practical and preferred at the present time, the present invention is not limited to only the disclosed embodiments, but the technical idea described in the claims. And various modifications and equivalent configurations belonging to the technical scope.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a prior art drum-like barrel used for transporting uranium oxide.
FIG. 2 is a partially cutaway cross-sectional perspective view showing a container according to the present invention.
FIG. 3 is a cross-sectional view showing one of the inner containers according to the present invention.
FIG. 4 is an enlarged partial sectional view showing a laminated side wall of the inner container of the present invention.
FIG. 5 is a partial cross-sectional view showing a preferred connecting portion between the lid of the inner container and the mounting flange of the preferred embodiment of the present invention.
FIG. 6 is a cross-sectional view showing another form of connection between the side wall and the lid of the inner container.
7 is an end view of a lid used for the inner container of FIG. 8. FIG.
FIG. 8 is a partial cross-sectional view of the inner container showing another form of connection between the lid and the inner container.
FIG. 9 is a top view of the outer container body.
FIG. 10 is a side view of the outer container body.
FIG. 11 is an enlarged partial cross-sectional view of a fusible plug provided on the side wall of the outer container main body.
FIG. 12 is a partially cut-out bottom view showing the lower surface of the lid for the container main body.
13 is a side view of the lid shown in FIG. 12. FIG.
FIG. 14 is a partially cutaway side view of the container of the present invention.
[Explanation of symbols]
20 Container 22 Outer container body 24 Lid 26 Side wall 28 Bottom wall 30 Top wall 32 Inner container 34 Sleeve 36 Bottom wall 38 Side wall 40 Inner wall 42 Outer wall 44 Nuclear poison 46 Nuclear moderator 48 Ceramic layer 50 Mounting flange 52 Groove 60 Mounting flange 70 Clamp 74 Mounting flange 90 Low density polyurethane foam 92 High density polyurethane foam 96 Guide 98 Plastic plug 100 Screw socket 102 Top wall 104 Side wall 106 Reinforcing gusset 110 Foamed plastic material 112 Recess

Claims (16)

Uranium oxide comprising an outer container (22) and a plurality of storage inner containers (32) arranged in a regular arrangement spaced apart from each other in the outer container (22) and spaced from the outer container (22). A transport container (20),
Each of the storage inner containers (32) has a cylinder for containing a predetermined amount of uranium oxide, and the cylinder includes a sealed top (L), a sealed bottom (36), a nuclear poison (44), and a nuclear moderator. And a cylindrical side wall (38) laminated around (46), and a space between the storage inner container (32) and between the storage inner container (32) and the outer container (22). Is filled with plastic material ,
The plastic material includes first and second separate plastic foam materials (90, 92) of different densities;
The first plastic foam material (90) exists in a gap between the storage inner containers (32), and the second plastic foam material (92) defines the outer container (22) and the first plastic. Surrounding the first plastic foam material (90) with the outermost portion of the foam material (90);
The transport container (20), wherein the second plastic foam material (92) has a higher density than the first plastic foam material (90 ).  The transport container (20) according to claim 1, wherein the outer container (22) and the storage inner container (32) are made of stainless steel.  The transport container (20) of claim 1, wherein the nuclear poison (44) comprises cadmium.  The transport container (20) according to claim 3, wherein the nuclear moderator (46) comprises polyethylene.  2. A transport container (20) according to claim 1, characterized in that the space is filled with polyurethane plastic foam material.  The outer container (22) includes a container body having a side wall and a bottom wall (26, 28) and a lid (24) for covering and sealing the container body, and the lid (24) is fireproof. The transport container (20) of claim 1, further comprising a layer of impact-resistant material. 7. A transport container (20) according to claim 6 , characterized in that the material in the container body and the lid (24) comprises a foamed plastic material. A plurality of recesses (112) for receiving a protruding upper end of the storage container (32) disposed in the container body below the foam plastic material (110) in the lid (24). 8) A transport container (20) according to claim 7 , characterized in that The foamed plastic material (110) transport container according to claim 7, characterized in that it consists of foam with a higher density than the first plastic foam (90) in the cover (24) (20).  A transport container (1) according to claim 1, wherein the outer container (22) comprises a plurality of generally cylindrical upstanding sleeves (34) spaced apart in a regular array to accommodate the storage container. 20).  Each of the storage inner containers includes a lid (24), a container body part having a lid mounting flange, and a seal between the lid (24) and the container body part, wherein the lid (24) 2. A transport container (20) according to claim 1, characterized in that it is bolted to a lid mounting flange.  Each of the storage inner containers includes a lid (24), a container body part having a lid mounting flange, and a seal between the lid (24) and the container body part, wherein the lid (24) 2. A transport container (20) according to claim 1, characterized in that it is clamped to a lid mounting flange.  Each of the storage inner containers includes a lid (24) and a container body part having a lid mounting roll flange, and the lid (24) has a peripheral flange that covers the lid mounting flange. The transport container (20) according to claim 1.  The side wall of the storage inner container contains a ceramic material, and each side wall of the storage inner container is composed of a stainless steel layer, a cadmium layer, a polyethylene layer, the ceramic material layer, and a stainless steel outer layer toward the outside. The transport container (20) according to claim 1, characterized by: Having a plug to expose the plastic foam material to the surrounding environment through the wall of the outer container (22) before Kigai container (22) is 1 or more plug through the wall to melt at a predetermined temperature The transport container (20) according to claim 1, characterized by:  2. Transport container (20) according to claim 1, characterized in that the storage inner containers are arranged in a 3x3 regular array in the outer container (22).

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